1. Field of the Invention
This invention relates to a recording medium driving device for driving a recording medium on which are formed plural tracks substantially parallel to one another, and to a tracking method for tracking a head with respect to the tracks formed on the recording medium substantially parallel to one another.
2. Description of the Related Art
Among conventional recording/reproducing apparatus for recording/reproducing 3.5 inch flexible magnetic discs, there is known an apparatus of the specifications in which a flexible magnetic disc is run in rotation at an rpm of the order of 300 to 600 rpm for recording/reproduction. These specifications are referred to hereinafter as the lower-order specifications. The flexible magnetic disc, recorded or reproduced on this recording/reproducing apparatus of the lower-order specifications, has a post-formatting recording capacity of approximately 1.44 Mbyte.
In recording/reproducing information signals on this recording/reproducing apparatus of the lower-order specifications, a stepping motor is used to effect tracking of the magnetic head with respect to each data track. That is, when recording/reproducing information signals for a recording medium of the lower-order specifications, the magnetic head is moved stepwise by the stepping motor along the radius of the magnetic disc for positioning the magnetic head on each data track.
On the other hand, it is required of the flexible magnetic disc to be of such specifications in which the recording density is higher than that of a disc of lower-order specifications and in which the rotational velocity is of the order of approximately 1200 to 3600 rpm for recording/reproduction to improve its recording density or data transfer rate. These specifications are referred to hereinafter as the upper-order specifications. It is required of the flexible magnetic disc used in the upper-order specifications to be of a reduced track width to increase the recording capacity to the order of 150 to 650 Mbyte.
Recently, attempts are being made to develop a recording/reproducing apparatus capable of recording/reproducing both the flexible magnetic discs of the widely used lower-order specifications and those of the upper-order specifications.
On the flexible magnetic discs of the upper-order specifications, there are pre-recorded the position information specifying the positions of the data tracks and the tracking information. With the recording/reproducing apparatus, the magnetic head can be tracked onto the respective data tracks by detecting this position information. In the recording/reproducing apparatus configured for recording/reproducing the flexible magnetic disc of the above-mentioned upper-order specifications, the magnetic head is moved radially of the recording medium, using a voice coil motor, in order to secure followup characteristics. Thus, with the recording/reproducing apparatus of the upper-order specifications, the magnetic head can be tracked onto the targeted data track to effect recording/reproduction by detecting the position information and applying tracking servo to the voice coil motor even though the track pitch is reduced as compared to that of the above-mentioned recording medium of the lower-order specifications.
However, with the recording/reproducing apparatus for recording/reproduction for both the flexible magnetic discs of the lower-order specifications and those of the upper-order specifications, the position information cannot be detected in the same manner as when recording/reproducing the flexible magnetic disc of the upper-order specifications because the position information is not recorded on the above-mentioned flexible magnetic disc of the lower-order specifications.